David --
Thanks for your reply.
You write:
> replace \def\Tsub[#1] by \newcommand\Tsub[1][] if you want
> to remain unspoiled by primitive tex syntax:-)
Well, I knew that. The question is whether the old
admonition has been made redundant.
-- Bill
> On 13 October 2017 at 23:27, William F Hammond
> <hmwlfsr at yahoo.com> wrote:
>> David Carlisle writes in part:
>>>>> you could use a definition such as \def\Tsub[#1]{T_{#1}}
>>> then $\Tsub[1]$
>>>> Have LaTeX Project members abandoned the view that TeX
>> primitives (in this case \def) don't belong in user-level
>> LaTeX documents?